Painless fissures?

I've been dealing with painless bleeding during bowl movements since last November. Went to the GI and he diagnosed me with a fissure based on physical examination. Followed his advise and all was good for 2-3 months and then the bleeding started again. Went back to the doctor about a month later and he didn't notice anything out of the ordinary. Two months on and all is going well..until today. Stomachs been kinda weird the last few days, frequent BMs mostly. Had a large BM today and bled a good bit. I'm getting worried that this isn't a fissure. I want to get a second opinion and would honestly feel better if I got a colonoscopy.